1090 Marvels of the Universe 
3.0 am. than at any other time. It is not 
easy to explain the meaning of these definite 
variations, and the possibility of explanation 
is rendered the more difficult by reason of 
the fact that the Earth is nearer the Sun in 
the winter than in the summer. Moreover, 
the distribution of the Radiant Points is very 
unequal over the visible heavens. They are 
far more numerous at and around the IInd 
Hour of Right Ascension than they are at 
and around the XIIth Hour of Right Ascen- 
sion. These discrepancies are no doubt partly 
real, but are also in part due to the differ- 
ence in the duration of night, when those 
two portions of the heavens are above the 
horizon in the Northern hemisphere, where 
meteor observations have hitherto been chiefly 
carried on. 
METEORS. It is time to pass on to those other Lumin- 
A flight of telescopic Meteors. ous Meteors which are probably identical with 
Shooting Stars in their nature, but which manifest themselves in a much more striking and 
pretentious form. These we call “ Fire-balls.” They appear suddenly and are usually noiseless, 
though sometimes an explosion is heard, which may or may not result in the descent to the 
Earth of an Aérolite or the broken-up fragments of an Aérolite. Their form is generally 
pear-shaped, the thin end of the pear giving forth sparks seemingly of incandescent matter 
proceeding from an incandescent nucleus. 
These sparks, whatever may be their nature, often remain visible for many minutes, and drift 
slowly away from the point of apparition, doubtless under the influence of wind-currents. 
The question will naturally be asked, What 
are these objects which we have been con- 
sidering ? Have they any physical existence 
when we see them, or are they mere optical 
manifestations ? It cannot be doubted that 
at some moment they have a physical, and 
probably solid, existence ; that Shooting Stars 
are small masses of matter which first become 
incandescent and burn away as they enter our 
atmosphere ; whilst Fire-balls are very much 
larger masses of more solid material, which 
also become incandescent and burn and burst 
into fragments of sufficient size to hold to- 
gether and fall to the Earth. This last state- 
ment seems sufficiently proved by the fact 
that not only many Aérolites (i.e., stones from 
the air—Gr.) have been found upon the surface 
of.the Earth, but have been found while still 
warm to the touch. As to where they origin- 
METEORS. ally came from and why they should visit the 
The Radiant Point of the Geminids, December | 2th. Earth we have no information—at any rate, 
